• 제목/요약/키워드: Atomic emission

검색결과 646건 처리시간 0.031초

A comparative evaluation of $CO_2$ and erbium-doped yttrium aluminium garnet laser therapy in the management of dentin hypersensitivity and assessment of mineral content

  • Belal, Mahmoud Helmy;Yassin, Abdulaziz
    • Journal of Periodontal and Implant Science
    • /
    • 제44권5호
    • /
    • pp.227-234
    • /
    • 2014
  • Purpose: Dentin hypersensitivity is a potential threat to oral health. Laser irradiation may provide reliable and reproducible treatment but remains controversial. The present study aimed to evaluate the effects of $CO_2$ or erbium-doped yttrium aluminium garnet (Er:YAG) laser therapy, and to assess mineral content. Methods: Eighteen human single-rooted teeth affected with advanced periodontitis were obtained. Buccal and lingual surfaces were planed to form 36 specimens. Ethylenediaminetetraacetic acid gel (24%) was applied to remove the smear layer and simulate hypersensitive teeth. The experimental groups were: group 1, control (no irradiation); group 2, $CO_2$ laser (repetitive pulsed mode, 2 W, $2.7J/cm^2$); and group 3, Er:YAG laser (slight contact mode, 40 mJ/pulse and 10 Hz). To evaluate dentinal tubule occlusion, six specimens per group (2-mm thickness) were prepared and observed using scanning electron microscopy (SEM) for calculation of the occlusion percentage. To evaluate the mineral content, six specimens per group (0.6-mm thickness) were used, and then the levels of Ca, K, Mg, Na, and P were measured by inductively coupled plasma-atomic emission spectrometry. In addition, the surface temperature of the specimens during laser irradiation was analyzed by a thermograph. Results: The SEM photomicrographs indicated melted areas around exposed dentinal tubules and a significantly greater percentage of tubular occlusion in the $CO_2$ and Er:YAG laser groups than the control, and in the Er:YAG group than the $CO_2$ laser group. In addition, no significant differences were noted among the experimental groups for the mineral elements analyzed. The $CO_2$ laser group showed an evident thermal effect compared to the Er:YAG group. Conclusions: $CO_2$ and Er:YAG laser are effective in treating dentin hypersensitivity and reducing its symptoms. However, the Er:YAG laser has a more significant effect; thus, it may constitute a useful conditioning item. Furthermore, neither $CO_2$ nor Er:YAG lasers affected the compositional structure of the mineral content.

원자발광광도법에 의한 란탄족 원소의 정밀분석에 관한 연구 (제 1 보) 희토류-EDTA 용리액에 의한 희토류 원소의 분리 회수 (Study on the Precision Analysis of Lanthanides by Atomic Emission Spectroscopy (I). Separation of Rare Earth Elements Using Ln-EDTA Eluent)

  • 차기원;오진희;하영구;김하석
    • 대한화학회지
    • /
    • 제36권5호
    • /
    • pp.692-696
    • /
    • 1992
  • $NH_4^+형 양이온 교환수지와 희토류-EDTA 용리액을 사용하여 희토류 원소 혼합물에서 원하는 한 원소를 분리 회수하는 연구를 하였다. NH_4^+형 양이온 교환수지에 희토류 혼합물을 흡착시키고, La-EDTA 용액으로 용리하면 수지에 흡착된 희토류 원소중 La^{3+} 이온 외의 희토류 원소는 용리된다. 수지에 남아있는 La^{3+}은 EDTA 용리액으로 용리하여 분리한다. Ce^{4+}만 선택적으로 분리하고자 할때는 La-EDTA 대신 Ce-EDTA로 용리하고 수지에 남은 Ce^{4+}을 EDTA로 용리하면 된다. 이때 분리 구조는 다음과 같다. 흡착과정 : 3RNH_4 + Ln^{3+} = R_3Ln + 3NH^{4+}, La-EDTA 용리 : R_3Ln + La-Y- = R_3La + Ln-Y^-, EDTA 용리 : R_3La + HY^3- = La-Y + RH + 2R-.$

  • PDF

교통량 과밀 도로주변의 토양과 가로수, 대기중 Pb, Cu, Zn 중금속 농도와 그 상관성에 관한 연구 (Pb, Cu, Zn Contaminants and Their Correlation of Soil, Leave and Bark of Ginkgo. B and Ambient Air Adjacent to a Heavy Traffic Road Side)

  • 박기학
    • 한국환경보건학회지
    • /
    • 제18권2호
    • /
    • pp.19-25
    • /
    • 1992
  • The study was carried out to investigate the correlation between the heavy metals emitted by the motor vehicles with the heavy traffic road side environment (soil, leave, bark, ambient air). The Pb, Cu, Zn contents in road side soil sand leaves, barks from Ginkgo, biloba and ambient air adjacent to the heavy traffic road side from June to August, 1992 Suwon city were analyzed by Atomic absorption spectrometry and Inductively coupled plasma emission spectrophotometry. The results were as follows: 1) The high levels of heavy metals concentration were Pb, at city-terminal in soil (186 $\mu$g/g), Cu, at city-terminal in soil (221 $\mu$g/g), Zn, at city-terminal in ambient air (252 $\mu$g/m$^{3}$). 2) The low leves of heavy metals concentration were Pb, at North-gate in ambient air (1.65$\mu$g/m$^{3}$), Cu, at North-gate in ambient air (4 $\mu$g/m$^{3}$), Zn, at North-gate in ambient air (15.31$\mu$g/m$^{3}$). 3) The regional distribution of Pb, Cu, Zn in road side soils, leaves and barks from Ginkgo, biloba, ambient air show high levels in turn, city4erminal, Guan Sean Dong, South gate, North gate. 4) The concentration of heavy metals (Pb, Cu, Zn) in soils, leaves, barks, ambient air was highly correlated with the traffic volume of the sampling sites (r=0.64~0.96). To conclude that the high levels of Pb, Cu, Zn contaminations were positively related to motor vehicles-borne pollutants and road side soils, trees, ambient air adjacent to a high density building area with low road coverage and heavy traffic volume were reflected strongly by the hazardous pollutants emitted by motor vehicles.

  • PDF

Growth and characterization of periodically polarity-inverted ZnO structures grown on Cr-compound buffer layers

  • Park, J.S.;Goto, T.;Hong, S.K.;Chang, J.H.;Yoon, E.;Yao, T.
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
    • /
    • pp.259-259
    • /
    • 2010
  • Periodically polarity inverted (PPI) ZnO structures on (0001) Al2O3 substrates are demonstrated by plasmas assisted molecular beam epitaxy. The patterning and re-growth methods are used to realize the PPI ZnO by employing the polarity controlling method. For the in-situ polarity controlling of ZnO films, Cr-compound buffer layers are used.[1, 2] The region with the CrN intermediate layer and the region with the Cr2O3 and Al2O3 substrate were used to grow the Zn- and O-polar ZnO films, respectively. The growth behaviors with anisotropic properties of PPI ZnO heterostructures are investigated. The periodical polarity inversion is evaluated by contrast images of piezo-response microscopy. Structural and optical interface properties of PPI ZnO are investigated by the transmission electron microcopy (TEM) and micro photoluminescence ($\mu$-PL). The inversion domain boundaries (IDBs) between the Zn and the O-polar ZnO regions were clearly observed by TEM. Moreover, the investigation of spatially resolved local photoluminescence characteristics of PPI ZnO revealed stronger excitonic emission at the interfacial region with the IDBs compared to the Zn-polar or the O-polar ZnO region. The possible mechanisms will be discussed with the consideration of the atomic configuration, carrier life time, and geometrical effects. The successful realization of PPI structures with nanometer scale period indicates the possibility for the application to the photonic band-gap structures or waveguide fabrication. The details of application and results will be discussed.

  • PDF

Transparent Conductive Films Composite with Copper Nanoparticle/Graphene Oxide Fabricated by dip Process and Electrospinning

  • 김진운;김경민;김용호;김수용;조수지;이응상;석중현
    • 한국진공학회:학술대회논문집
    • /
    • 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
    • /
    • pp.382.2-382.2
    • /
    • 2014
  • We explain a method to fabricate multi-layered transparent conductive films (TCF) using graphene oxide (GO), copper powder and polyurethane (PU) solution. The flexible graphene nanosheets (GNSs) serve as nanoscale connection between conductive copper nanoparticles (CuNps) and PU nanofibers, resulting in a highly flexible TCF. To fabricate conductive films with high transmittance, polyurethane (PU) nanofibers were used for a conductive network consisting of CuNps and GNSs (CuNps-GNSs). In this experiment, copper powder and graphene oxides were mixed in deionized water with the ultrasonication for 2 h. NaBH4 solution is used as a reduction agents of CuNps and GNSs (CuNps-GNSs) under a nitrogen atmosphere in the oil bath at 100% for 24 h to mixed. The purified and dispersed CuNp-GNS were obtained in deionized water, and diluted to a 10wt.% based on the contents of GNSs. Polyurethane (PU) nanofibers on a PET substrate were formed by electrospinning method. PET slides coated with the PU nanofibers were immersed into CuNp-GNS solution for several second, rinsed briefly in deionized water, and dried to obtain self-assembled CuNp-GNS/PU films. The morphology of the multi-layered films were characterized with a field emission scanning electron microscope (FE-SEM, Hitachi S-4700) and atomic force microscope (AFM, PSIA XE-100). The electrical property was analysed by the I-V measurement system and the optical property was measured by the UV/VIS spectroscopy.

  • PDF

신안침몰선 인양 중국 동전의 화학조성 (CHEMICAL COMPOS IT80N OF AHCIENT CH INESE COINS RICOVIRID FROM THI SHINAN SHIPWRECK)

  • 이창근;강대일
    • 보존과학연구
    • /
    • 통권10호
    • /
    • pp.1-40
    • /
    • 1989
  • Between 1976 and 1984 approximately 26.7 tons of Chinese coins were recovered from a shipwreck which was found at the seabed of the Shin an area in the south-western coast of the Korean peninsula. Elements, Cu, Pb, Sn, Fe, Sb, As, Zn, Ag, Ni, Co and Mn, of 54 pieces of the coins were determined by Inductively Coupled Plasma Atomic Emission Spectroscopy(ICP-AIS). The result shows that Ch, Pb, and Sn were found to be major elements roughly the coins with the ratio of 7 : 2 : 1, respectively. Trace elements were classified into 3 levels according to the avarage concentration : Fe,As and Sb(0.1-0.5%), Ag, Mi, Co and Zn(100-1000ppm) and Mn(10ppm). Some systematic tendencies are observed in the composition change with a function of their minting ages .The Wuzhu coins(오수전) from the Eastern Han dynasty(A.D.25-219 )are much more abundant in Cu than the coins of Tang dynasty(A.D.618-907) and later periods. Major element compositions of the Kai -tong Vuan-Bao(개통원보) coins from the Tang dynasty, were remarkably variable. In general, however, the Tang dynasty coins were much more abundant in Cu than the Song dynasty(A.S.S60-1279) coins. The amount of major elements Cu and Sn decreases while that of Pb in creasesby passage of age from the Bei Song dynasty(A.D.960-1127) to later Nam Song dynasty (A.D.1127-1279 ). It means that the quality of coins mere degraded. The amounts of trace elemends(Fe, As, Co, Hn) increases with the above age. High amounts of trace elements are supposed to be a reflection of immaturity of minting techniques or use of impurity-rich raw materials. The Jin dynasty(A.D.1125-1234) coins are found to be rich in Sn and thus contain Pb as the third component. It is quite different from the coins of the Song dynasty. The Zhi-dai Tong-Bao(지대통보) coins of the Yuan dynasty from A.0.1310 are much more abundant in Cu and Sn than those of the Nam Song dynasty .

  • PDF

교정용 와이어의 표면특성에 미치는 TiN 및 ZrN 코팅영향 (Effects of TiN and ZrN Coating on Surface Characteristics of Orthodontic Wire)

  • 김원기;김도영;최한철
    • 한국표면공학회지
    • /
    • 제41권4호
    • /
    • pp.147-155
    • /
    • 2008
  • The dental orthodontic wire provides a good combination of strength, corrosion resistance and moderate cost. The purpose of this study was to investigate the effects of TiN and ZrN coating on corrosion resistance and physical property of orthodontic wire using various instruments. Wires(round type and rectangular type) were used, respectively, for experiment. Ion plating was carried out for wire using Ti and Zr coating materials with nitrogen gas. Ion plated surface of each specimen was observed with field emission scanning electron microscopy(FE-SEM), energy dispersive X-ray spectroscopy(EDS), atomic force microscopy(AFM), vickers hardness tester, and electrochemical tester. The surface of TiN and ZrN coated wire was more smooth than that of other kinds of non-coated wire. TiN and ZrN coated surface showed higher hardness than that of non-coated surface. The corrosion potential of the TiN coated wire was comparatively high. The current density of TiN coated wire was smaller than that of non-coated wire in 0.9% NaCl solution. Pit nucleated at scratch of wire. The pitting corrosion resistance $|E_{pit}-E_{rep}|$ increased in the order of ZrN coated(300 mV), TiN coated(120 mV) and non-coated wire(0 mV).

Installation for Preparing of Nanopowders by Target Evaporation with Pulsed Electron Beam

  • Sokovnin S. Yu.;Kotov Yu. A.;Rhee C. K.
    • 한국분말재료학회지
    • /
    • 제12권3호
    • /
    • pp.167-173
    • /
    • 2005
  • Production of weakly agglomerated nanopowders with the characteristic size of about 10 nm and a narrow particle size distribution is still a topical problem especially if the matter is an acceptable output (>50 g/hour), a high purity of the final product, and a low (energy consumption. The available experience and literature data show that the most promising approach to production of such powders is the evaporation-condensation method, which has a set of means for heating of the target. From this viewpoint the use of pulsed electron accelerators for production of nanopowders is preferable since they allow a relatively simple adjustment of the energy, the pulse length, and the pulse repetition rate. The use of a pulsed electron accelerator provides the following opportunities: a high-purity product; only the target and the working gas will interact and their purity can be controlled; evaporation products will be removed from the irradiation zone between pulses; as a result, the electron energy will be used more efficiently; adjustment of the particle size distribution and the characteristic size of particles by changing the pulse energy and the irradiated area. Considering the obtained results, we developed a design and made an installation for production of nanopowders, which is based on a hollow-cathode pulsed gas-filled diode. The use of a hollow-cathode gas-filled diode allows producing and utilizing an electron beam in a single chamber. The emission modulation in the hollow cathode will allow forming an electron beam 5 to 100 ms long. This will ensure an exact selection of the beam energy. By now we have completed the design work, manufactured units, equipped the installation, and began putting the installation into operation. A small amount of nanopowders has been produced.

가압분무기의 성능 평가와 특성 비교 (Analytical Performance Evaluation of Pneumatic Nebulizers and Comparison of Their Characteristics)

  • 박창준;한명섭;송선진;이동수
    • 분석과학
    • /
    • 제15권2호
    • /
    • pp.120-126
    • /
    • 2002
  • 유도결합 플라스마 질량분석기(ICP-MS)와 유도결합 플라스마 원자방출분광기 (ICP-AES)를 이용하여 상업적으로 유통되고 있는 4 종의 분무기(Meinhard, ESI PFA, Cross-flow, Babington)와 한국표준과학연구원(KRISS)에서 직접 제작한 분무기인 KRISS Inert 분무기와 KRISS conespray 분무기의 성능을 평가하였다. 각 분무기의 압력, 시료주입량의 변화에 따른 시료주입 효율을 조사하였으며 ICP-MS와 ICP-AES에 연결하였을 때 시료주입량의 변화에 따른 감도, 안정성, 바탕선 세기, 산화물과 수소화물의 생성 비율을 조사하였다. 시료의 종류, 시료 양의 제한성, 분석기기의 종류, 분석 원소에 따라 가장 적합한 분무기를 선택해야 높은 감도, 낮은 바탕값, 안정한 신호세기 등의 좋은 분석결과를 얻을 수 있음을 알 수 있었다.

Gender-Related Differences in a Process of the Age-Dependent Alterations of the Elements in Monkey Sino-Atrial Node

  • Satoh, Hiroyasu;Tohno, Setsuko;Minami, Takeshi;Oishi, Takao;Hayashi, Motoharu;Tohno, Yoshiyuki
    • The Korean Journal of Physiology and Pharmacology
    • /
    • 제14권5호
    • /
    • pp.249-256
    • /
    • 2010
  • Gender differences in the trace elements of monkey sino-atrial (SA) node were investigated in a process of age-dependent alterations. Sixty hearts from Japanese and rhesus monkeys (30 male and 30 female) used were aged ranging from 1-day- to 30-year-old. The elements were analyzed using an inductively coupled plasma-atomic emission spectrometer (ICP-AES). Advancing age decreased all the trace elements. Ca, P, S and Mg significantly decreased. The correlation coefficients of Ca and P were $-0.178{\pm}0.081$ (p<0.05) and $-0.088{\pm}0.022$ (p<0.05) in male (n=30), and $-0.095{\pm}0.026$ (p<0.05) and $-0.069{\pm}0.017$ (p<0.05) in female (n=30), respectively. The age-dependent coefficients for Fe/Ca, Zn/Ca, Fe/P, Fe/S, Zn/S, Fe/Mg and Zn/Mg were exhibited markedly in male, but all was less in female. In gender-related differences, only a ratio of P/Ca (p<0.05) was significantly observed with ageing. The trace elements such as Cu, Se and Sn were less detected in the SA nodes. These results indicate that the age-dependent changes in the ratios of elements are appeared more rapidly in male monkey SA node, and the gender difference is observed in ratio of P/Ca. The different attenuations may be involved with the age- and gender-related SA nodal functions.